The Algae Plague
Algae (pronounced AL-jee) are among the simplest forms of marine plant life. They lack leaves, roots, flowers, seeds, and all the other things we normally associate with plants, in other words they are very basic – and often annoying!
The term ‘algae’ is used to refer to all forms of marine life that are capable of photosynthesis (converting sunlight into energy). Some forms of algae, however, rely entirely on external supplies of energy (in the form of protein and fish waste in the water) for food.
Your tropical fish tank does not want algae. Algae is definitely an unwanted visitor – it’s a real eyesore. Unfortunately, certain levels of algae are to be expected; small amounts are inevitable wherever there’s light, nutrients, and water in combination.
When algae levels get high enough to be visible to the naked eye, you’ve got a surplus. Not maintaining your aquarium regularly, will lead to regular growths of algae obscuring your fish, making the water smell, and generally detracting from the aesthetic appeal of your tank.
But how do you get rid of Algae?
The cure depends on the type of algae you have, since each one needs to be treated in a specific manner.
The most common forms of algae to affect tropical fish tanks are: * brown algae * green algae * blue-green algae * green water
Brown algae is usually the first to appear in a newly established tank. It is pretty easy to see: it appears like cloudy brown slime growing along the sides and bottom of your aquarium, as well as clinging onto gravel, rocks, and ornaments.
Limiting the light available won’t make any difference to this type of algae, because it is capable of growing at low-lighting levels. Instead, you need to cut right back on the nutrients available for sustaining its growth – which means feeding your fish less.
High protein levels in the tank, derived from excessive fish food, accelerate this algae’s growth.
NOTE: even if your fish are eating all the food you give them, you may not be feeding them the right amount. Fish are natural opportunists, which means they’ll eat everything that’s available regardless of how much you feed them.
If fish are overeating, they simply excrete the undigested food – which then floats around in the tank, feeding the algae instead! Prevent this by making sure you follow the directions stringently on the fish-food package. Then you can be certain that you’re minimizing nutrient levels appropriately.
Also, make sure you’re maintaining your tank adequately with enough water changes and gravel and filter cleanings.
If brown algae occurs in an established aquarium check the phosphate and nitrate levels, as too much of either will encourage the growth of the algae.
If the problem continues you can use algae-eaters. These are bottom-dwelling fish – such as the American-flag fish and the Siamese algae eater – which feed on algae, and are commonly stocked by pet stores and fish traders.
These fish make quick work of your brown algae problem!
Green algae will appear in just about any tank with plenty of light.
Fortunately, it is easy to remove (it doesn’t cling to the glass too much) and most algae-eaters will consume it with gusto.
For green algae, make sure you’re minimizing the protein in the tank, as you would for brown algae. Start by cutting the fish-food back by one quarter, and pay close attention to the appearance of your fish. If their bodies become flat and thin, they’re not eating enough. The optimum amount of food will maintain a slightly round-bodied appearance to your fish.
Keep your fish tank stocked with plenty of algae-eaters, and the problem should take care of itself (although it bears repeating that a certain amount of algae, particularly green algae, is to be expected).
Blue-green algae technically is not an algae in the true sense of the word – it is actually a form of bacteria, called cyanobacteria, which is capable of photosynthesis.
Cyanobacteria looks like a slimy coating in a number of greenish-blue shades, and produces wastes that can be toxic to your fish.
Fortunately, blue-green algae is easy to remove manually. It usually forms ‘sheets’ of hanging matter in the water, which can easily be scooped out.
Unfortunately it is that it’s pretty hardy and even after a thorough removal it will usually return the next day.
This algae is often caused by low levels of nitrates (usually in combination with high levels of phosphate), and an imbalance of bacteria in the water.
To get rid of blue-green algae block all light for a week, and siphon the dead algae out of the tank each day. Your plants will also by suffering by the seventh day, but they should recover just fine.
Add new bacteria pellets after every water change. These can be purchased from your pet store and aquarium supply dealer. Ask for bacteria pellets that remove ammonia and excess protein from the water.
Always keep up with your tank maintenance: keep everything clean, check the filter for clogging, make sure the lights are working adequately (blue-green algae needs light to survive, but good fluorescents are necessary to maintain an adequate balance of bacteria and plant life in the tank).
Green water in your tank appears as green, cloudy, and murky water.
This is a free-floating algae which hangs suspended in the water, giving it that characteristic opacity – in some cases, the water becomes so green that the fish are obscured.
Significant excess of light (usually sunlight, as opposed to too much fluorescent), cause this algae to flourish, or a problem with your water quality.
To treat Green Water block all sunlight from reaching your tank for up to one week. You can do this by draping fabric over your tank, or making sure that all the curtains remain drawn in the room where your aquarium is placed.
Also, keep your filter mesh as fine as you can: most generic filters come with pretty coarse mesh, so replace it with a fine-meshed sponge or use a diatomic filter (designed specifically to treat algal problems).
Remember to check the filter regularly to prevent clogging.
General algae prevention tips. Regular maintenance of your tank is one of the best preventative measures when it comes to algae.
- Change the water regularly
- Clean the aquarium regularly
- Use a UV filter in the tank
- Situate the tank away from direct sunlight
- Don’t overcrowd the fish
- Keep the food levels down
- Minimize aeration unless your aquarium is very well stocked: keep airstones and vents to a minimum
- Utilize your plants’ nitrate and phosphate absorbing capacity: stock your aquarium with plenty of fast-growing species like Ambulia and Egeria
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